http://www.google.com/url?q=http://68kmla.org/files/classicmac2.pdf&sa=U&ei=XM2BT-GYHePC0QXanNDoCQ&ved=0CBIQFjAA&usg=AFQjCNF5-gsy_RYr5hYYD99-vLUir362Kw

have a look at this file, probably you will find a reply, yoke connector J1 is known to go bad, as well as capacitor C1.